The use of electrical junction boxes is well known in the art. In new construction, the boxes are typically mounted to wall studs prior to placement of the wall on the studs. Conventional fasteners may be used in these situations to mount the boxes to the wall studs. However in many instances where electrical boxes must be installed on existing walls, such as in remodeling, the wall studs are not always readily accessible or in the desired location to permit securement of the electrical box thereto.
In these situations, certain electrical boxes, referred to as "cut-in" or "old work" boxes, are used where the boxes are inserted into an opening cut into the wall. The boxes are specifically constructed to include clamping hardware which enables the box to be clamped to the wall itself about the opening without regard to the location of the wall studs. These cut-in or old work boxes must be specifically constructed to include wall mounting hardware permitting mounting of the box directly to the wall without use of wall studs.
These specifically constructed boxes generally take two forms. The first includes boxes having swing-out clips. Examples of boxes of this type are shown in U.S. Pat. Nos. 4,332,330, 2,299,696, 2,272,846 and 1,957,844. The boxes shown in these patents include adjustable clips mounted on each box side wall. The clips are initially positioned within the interior of the box so that the box may be inserted into an opening in the wall which is sized to specifically accommodate the box. After the box is passed through the opening, the clips may be swung outwardly through the side walls to engage the back surface of the wall. These swing-out clips, however, are difficult to manipulate in the tight environment in which these boxes must be installed. Further the box must include passageways or slots through the side wall of the box to enable the clip to swing out from an internal position to an external position once the box is inserted through the wall opening. As may be appreciated, boxes having swing-out clips of this type require extensive fabrication and/or modification of existing box structure. Due to such extensive modification, many of these types of cut-in boxes are not listed by agencies such as Underwriters Laboratories (UL) and Canadian Standards Association (CSA).
Another type of cut-in box includes those boxes which have clips and screws mounted on the exterior surface of the side walls or the top and bottom walls of the box. Examples of boxes of this type are shown in U.S. Pat. Nos. 2,867,344, 2,801,019, 1,957,003 and 1,775,665. As the clips shown in these patents are mounted exteriorly of the box, they present a wide profile which requires a larger hole to be cut through the wall into which the box is to be mounted. Such a large opening may require extensive repair after the box is installed or must be used with a large cover plate to cover the opening.
Also, many of these boxes include complicated wall engaging mounting structures. Compression devices, toggle clips, snaps and the like such as shown in U.S. Pat. Nos. 4,120,473, 4,120,416, 2,776,774, 2,870,931 and 2,769,562 may also be used to secure the box to the wall. However many of these structures are difficult for the installer to easily operate.
Common to all of the above described boxes, is the fact that the boxes must be prefabricated or specifically modified to accommodate particular mounting hardware. This necessitates the installer carrying boxes which are specifically manufactured solely for old work or cut-in applications in addition to boxes for other applications.
It is therefore desirable to provide a mounting assembly which allows for the use of a standard electrical box in old work or cut-in applications.